Walther Bothe

Walther Bothe went to war in 1914, spent years in a Russian POW camp, and returned to Germany in 1920 to pick up where physics had left him. He developed coincidence circuits - devices that register only simultaneous events - and turned them on the Compton effect, cosmic rays, and the strange double life of radiation as both wave and particle. By 1930 he held a full professorship at Giessen; two years later he moved to Heidelberg's Physical and Radiological Institute, only to be forced out by the Deutsche Physik faction. To keep him from leaving the country, he was made director of the Physics Institute at the Kaiser Wilhelm Institute for Medical Research, where he built Germany's first working cyclotron and became a principal in the Uranverein, the wartime nuclear program that began in 1939. He shared the 1954 Nobel Prize in Physics with Max Born for the coincidence method and what it revealed. After his death in 1957, his institute was elevated to the Max Planck Society; the main building still carries his name.